The optical properties of the angle tuning, resonation thresholds, and conversion efficiency curves are simulated for CLBO and BBO crystal by using the Sellmeier equation and the energy conservation in type-Ⅰ and Ⅱ. The wavelength tuning ranges of 237～289 nm and 807～2793 nm, 404～2800 nm in type-Ⅰ and type-Ⅱ are obtained for CLBO-OPO by 213 nm pumped, respectively. The efficiency is obtained that the efficiency of CLBO is larger than that of BBO in type Ⅰ, and the efficiency of CLBO crystal is less than that of BBO in type Ⅱ, but the maximum efficiency is obtained in the ultraviolet waveband for CLBO than that of BBO crystal. It is proved theoretically that CLBO is a excellent ultraviolet crystal.